Mechanical refrigerator door opening system



Aprxl 29, 1969 H. G. THOMPSON MECHANICAL REFRIGERATOR DOOR OPENING SYSTEM Filed July 5, 1967 Sheet .Ww @AI/Z ATTORNEY April 29, 1969 H. G. THOMPSON 3,440,760

MECHANICAL REFRIGERATOR DOOR OPENING SYSTEM Filed July 5, 1967 Sheeil of 3 ATTORNEY April 29, 1969 H. G. THOMPSON 3,440,750

MECHANICAL REFRIGERATOR DOOR OPENING SYSTEM Filed July s, 1967 sheet 3 @fz if A l a W /ff INVENTOR.

ATTOWEY United States Patent Office 3,440,760? Patented Apr. 29, 1969 3,440,760 MECHANICAL REFRIGERATOR DOOR OPENING SYSTEM Herbert G. Thompson, West Milton, Ohio, assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Filed July 3, 1967, Ser. No. 650,988 Int. Cl. Ef 5/12 U.S. Cl. 49-103 3 Claims ABSTRACT 0F THE DISCLOSURE In preferred form, a refrigerator door opening system including a power cylinder pivotally connected to the top of the refrigerator with a reciprocating piston rod directly connected to a rst refrigerator door by a depending link extending across the front of a second door alternately interconnected to the first door by a coacting latch mechanism between the two doors including a latch plate pivotally secured to one of the doors and a catch element fixed to the other of the doors interconnectingly engageable with the latch plate to cause concurrent opening movements of said doors and a latch plate release arm between the two doors engageable with the latch plate to release it from the catch element on alternate door opening operations of said power cylinder.

This invention relates to mechanical door opening systems and more particularly to a mechanical system for opening rst and second refrigerator doors at predetermined dilering rates.

In the manufacture of domestic refrigerators, it is desirable to conduct a number of preliminary tests to check the operational characteristics of the refrigerator units under conditions simulating those found under actual working conditions. For example, refrigerators are typically operated in humidity room tests to determine certain facts such as the power consumption of the refrigerator at different temperatures and humidity conditions; the recovery period following a number of door openings, before the food storage compartment reaches a desired temperature; the number of defrost cycles of operation that will occur under different temperature and humidity conditions and the like. In refrigerators that have a single door, these tests require connecting the door to a suitable operating device that will open and close the single door at a predetermined frequency. The single door opening and closing movements that occur during a predetermined part of a 24 hour period simulates actual working conditions.

The problem of simulating refrigerator door opening movements that occur during actual use, however, is made more difficult where the refrigerator has plural doors, for example, a door to a below freezing compartment and a door to a separate food storage compartment that is maintained above freezing. In refrigerators of this type, experience shows that the freezer compartment door is operated less frequently than the food storage compartment door. In the past, to simulate actual working conditions, such refrigerators have been connected to separate actuating devices programmed to operate at different frequencies. For example, in certain cases, separate hydraulic or fluid actuated power cylinders are connected to each of the doors and operated by separate timers to produce the desired test pattern.

An object of the present invention is to eliminate the need for the above-mentioned separate door actuating systems by the provision of a mechanical, plural door actuating system that includes a single power cylinder directly and continuously connected to a lirst refrigerator door and a two-piece coacting latch mechanism for alternately connecting the continuously operated door to a second refrigerator door to produce a variation in the frequency of door opening movements between the two doors so as to produce test conditions simulating those found in actual domestic refrigerator use.

A further object of the invention is to provide a mechanical door operating mechanism for a two-door domestic refrigerator including a power cylinder pivotally connected to the top of the refrigerator cabinet having its piston rod directly connected to a first refrigerator door to move it 'between opened and closed positions on each power cylinder operation and coacting linkage means between the first door and a second door including a movable latch plate on one of the doors and a fixed catch element on the other of the doors in interconnecting cngagement on one opening movement of the tirst door to produce concurrent opening movement of the second door and a latch plate release member operative to maintain the latch plate out of engagement with the catch element following concurrent opening movement to disconnect the second door from the lirst door on every other opening movement of the first door.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred embodiment of the present invention is clearly shown.

In the drawings:

FIGURE 1 is a View in perspective of a two-door refrigerator including the mechanical door opening system of the present invention;

FIGURE 2 is an enlarged fragmentary horizontal sectional view taken along the line 2 2 of FIGURE 1 looking in the direction of the arrows and showing coacting latch mechanism in the present invention;

FIGURE 3 is a view like FIGURE 2 showing the relative position of the parts of the latch mechanism with the two doors of the refrigerator in their full open position;

FIGURE 4 is a view like FIGURE 2 showing a latch mechanism release arm positioned to disconnect the two doors of the refrigerator;

FIGURE 5 is a view like FIGURE 2 showing the parts of the latch mechanism in the present invention disconnected;

FIGURE 6 is an enlarged vertical sectional view taken along the line 6 6 of FIGURE 1 looking in the direction of the arrows;

FIGURE 7 is an enlarged view in horizontal section taken along the line 7 7 of FIGURE 1 looking in the direction of the arrows and showing a power cylinder support cradle in plural positions;

FIGURE 8 is an enlarged view in horizontal section taken along the line 8 8 of FIGURE 1 looking in the direction of the arrows;

FIGURE 9 is an enlarged fragmentary vertical sectional view taken along the line 9 9 of FIGURE 2 looking in the direction of the arrows;

FIGURE 10 is an enlarged vertical sectional view taken along the line 10 10 of FIGURE 4 looking in the direction of the arrows; and

FIGURE 11 is a vertical sectional view taken along the line 11 11 of FIGURE 7 looking in the direction of the arrows and showing the power cylinder in place on its support cradle.

Referring now to the drawings, in FIGURE l is illustrated a refrigerator 20 including an outer shell or cabinet 22 having a rear wall, a top, spaced apart side walls and a base surrounding inner liner components 23,25

with thermal insulation located between the shell and liners. The inner liner components 23, 25 define an upper freezer compartment 24 and a food storage space or compartment 26 separated from the compartment 24 by an insulated divider wall or mullion 28.

The cabinet 22 has a front access opening 30 formed therein to the compartment 24 and also a front access opening 31 to the compartment 26.

An upper door 32 is support on the cabinet 22 at one side thereof by a top vertical hinge assembly 34 and an intermediate vertical hinge assembly 36 that together support the door 32 for swinging movement about a side vertic-al axis from an open position as seen in FIG- URE 1 to a closed position wherein a sealing gasket 35 formed continuously about the outer perimeter of the inside surface of the door 32 sealingly engages the front of the cabinet 22 about the access opening 30.

Additionally, the refrigerator 20 includes a lower or bottom door 38 supported on the shell or cabinet 22 by the intermediate hinge assembly 36 and a lower hinge assembly 40 for swinging movement about a side vertical axis from an open position, as seen in FIGURE 1, to a closed position where a continuously formed sealing gasket 41 on the inside surface of door 38 is held in sealing engagement with the front of the cabinet 22 -about the access opening 32.

In the illustrated arrangement, the upper door 32 includes a side door handle 42 attached thereto and the bottom door 38 includes a door handle 44 connected on the same side thereof- The two-door refrigerator 20 is a representative example of a domestic refrigerator that includes compartments maintained at different operating temperatures, for example, a freezer compartment operative in the F. range and a food storage compartment operative in the 35 F. range. In order to determine the operating characteristics of a domestic refrigerator of this type, it is desirable to open the doors under humidity test room conditions or the like at different frequencies corresponding somewhat to those encountered under ordinary working conditions. For example, in refrigerators of the illustrated type, it has been determined that the freezer door is opened about one half as often as the food storage compartment door. It will be understood that the illustrated freezer includes a suitable coolant system for example, a motor driven refrigerant compressor assembly that is operatively associated with suitable refrigerant condenser means, refrigerant expansion means, and refrigerant evaporator means to cool the compartment spaces 24, 26. An example of a domestic refrigerator of this type can be seen in United States Patent No. 3,004,400, issued Oct. 17, 1961 to L. J. Mann et al.

In accordance with certain principles of the present invention, the plural door refrigerator is associated with a mechanical door operating system 50 that is adapted to operate the doors 32, 38 into open positions and wherein the door 32 is alternately connected for movement with the door 38 so as to produce the door opening ratio between the food storage compartment door and the freezer compartment door of 2:1. More particularly, the mechanical door opening system 50 includes a fluid actuator assembly 52 that is operatively connected to the doors 32, 38 by an interconnecting link system 54. The doors 32, 38 are alternately connected to obtain the desired door opening ratio, set forth above, by a coacting door latching assembly 56.

More particularly, and as is best seen in FIGURES 1, 7 and l1, the actuator assembly S2 includes a cylinder connecting and locating plate 58 connected to the top of the refrigerator cabinet 22 by a plurality of screw elements 60 directed through adjusting slots 61 in the plate 58 at each corner thereof. Connected to the plate 58 at the approximate center thereof is a pivot pin 62 which is received within one of a plurality of position adjustment Openings 64 in the base of a power cylinder support cradle 66. The cradle 66 includes -a raised front flange 68 and a somewhat longer rear flange 69 to which the opposite ends of a power cylinder 70 are secured. The cradle 66 includes longitudinally directed upwardly inclined sides 71, 72 to align the cylinder 70 in a seated relationship on connecting flanges 68, 69. The power cylinder 70 has a piston member 74 located therein which is reciprocated by applying a pressure differential thereacross by suitable timed fluid supply means of a type well known in the art thereby to cause a piston rod 76 extending through one end of the cylinder 70 to be reciprocated into an extended or retr-acted position. In the illustrated arrangement, a fluid supply conduit 78 and a fluid exhaust conduit 80 are connected through a solenoid actuated four-way valve 81 to opposite sides of piston 74 to produce the operating pressure differential across piston 74. Pressure from conduit 78 is regulated by a valve 83 to control the rate at which doors are opened.

In one working embodiment, the power cylinder 70 is a unit supplied by Compressed Air Service Company of Dayton, Ohio as model number TF--Tiny Tim; the unit has a pressure rating of 150 p.s.i.g. and a 11A? inch bore; a 15 inch stroke; and a inch piston rod. The valve 81 is a model number 3C301 having a 115 volt coil and the flow control valve 83 is a model SCL-1 both supplied by the above mentioned company. The above stated actuator power cylinder and air supply system is only a representative example of such parts suitable for inclusion in the combination of the present invention.

As seen in FIGURE 6, the illustrated fluid actuator assembly 52 is connected to the interconnecting linkage system 54 by means including a piston rod extension 82 threadably received on the end of piston rod 76 and including an opening 84 therein which is aligned with an opening 86 in a linkage adaptor member 88 threaded into the upper end of a depending actuator rod 90. To obtain a fast connect between the piston rod 76 and actuator rod 90 in the illustrated arrangement, a link pin 92 directed through openings 84, 86 includes a knurled head 94 for ease in handling.

In the illustrated arrangement, the rod 90 is fastened by a connector element 96 to an upstanding rod 98 extending upwardly from a door support block 100 preferably constructed of wood. In the illustrated arrangement, the block 100 fits securely against the front face of doors 32, 38 to apply a uniform door closing force thereagainst.

As best seen in FIGURE 8, the wood block 100 is connected to an angle bracket 102 by suitable fastening means such as screws 104 and the angle bracket 102 is secured to a door bracket member 10,6 hooked about the side handle 44 and including a forward flange thereon connected to the angle bracket 102 by nut and screw fastening means 108. On one side surface of the block 100 is connected one leg 109 of a connecting plate 110 including a flange 112 directed across the top width thereof and a large surface area portion 114 located in engagement with a substantial planar extent of the front surface of door 38. The plate includes a plurality of holes 116 therein to lighten it without undesirably reducing the planar surface contact with the front surface of door 38. The brackets 102, 106 and connecting plate 110 along with the block 100 define a reinforced connection between the actuator assembly 52 and the door 38 and the coacting parts of the latch mechanism 56.

In the illustrated embodiment of the invention, the latch mechanism 56 includes a latch plate carrying subassembly 117 secured to the bottom door 38 at the upper flange 112 of plate 110 and further includes a catch element and latch release arm carrying subassembly 118 secured to the lower edge of the upper door 32.

It should be understood that the subassemblies of the latch mechanism 56 are susceptible to a reverse location,

namely, with the subassembly 117 being secured to the upper door 32 and the subassembly 118 secured to the upper edge of the lower door. The important point being that subassembly 117 is located on a door that is interconnected directly toan actuator assembly like 52 in the illustrated embodiment.

With particular reference to FIGURES 2 through 5 and 9, the movable latch plate subassembly 117 comprises a door mounting plate 120 fastened by screws and nuts 122 to the top flange 112 and by a counter sunk at headed screw 124 to the top of the lower door 38. The plate 120 is hooked over the back of the door 38 at 126 for securing platel 110 on the door 38. A pivot pin 128 secured to the plate 120 adjacent the front edge thereof extends upwardly through a movable latch plate member 130 which has an upstanding tab 132 thereon secured to one end of a coiled tension spring 134 having the opposite end thereof secured to an upstanding tab 136 on the plate 120 whereby the plate 130 is resiliently urged against an upwardly struck stop 138 on the support plate 120. The plate 130 includes an opening 139 for access to the underlying support plate connecting screw 124.

The movable latch plate 130 has a weighted member 140 supported on the inside end thereof across its width over-lying the support plate 120 closely adjacent the point at which it is hooked to 126. The opposite end of the plate 130 is inclined upwardly at 142 and the inclined portion 142 connects to a flat, forwardly located shoulder 144 extending across the full front width of the member 130. The spring 134 in addition to biasing the plate 130 about its pivot point to its stop position as seen in FIGURES 2, 3 and 5 also serves the function of tilting the front shoulder 144 upwardly about the pivot pin 128 as seen in FIGURE 10 under certain operating conditions of the coacting parts of the latch mechanism 56.

The upwardly inclined portion 142 is cut-out at 146. An insert member 148 has a tapered end thereon located through the opening 146 in portion 142 and is secured t0 the shoulder 144 by suitable means such as soldering to reinforce a front corner portion of member 130 that is periodically located in operative engagement with a latch releasing arm 150.

The catch carrying subassembly 118 more particularly comprises a mechanism support plate 152 hooked over the bottom edge of the upper door 32 at 154 and being connected thereto by suitable fastening means (not shown). The front edge of the plate 152 extends forwardly of the front surface of both doors 32, 38 and inv front of the mechanism subassembly 117 as best seen in FIGURE 9. On the front part of the plate 152 is located a depending catch member 156 including a threaded stud 158 thereon secured to the plate 152 by a nut 160. As best seen in FIG- URE 9, when both doors 32, 38 are closed the catch element 156 sits immediately forwardly of the upper shoulder 144 on latch plate 130.

The plate 152 also carries a p-in 162 that is connected to the elongated latch releasing arm 150 for pivotally securing it to the plate 152. The plate 152 also includes a downwardly struck tab 163 thereon (FIGURE 4) secured to one end of an elongated, coiled tension spring 164 having the opposite end secured to a connecting point 166 on the arm 150 intermediate the pivot pin 162 and an end 168 of the arm 150 located adjacent the mullion 28 between the doors 32, 38 when they are closed. The end 168 carries a roller member 170 which is secured by a rivet 172 to the arm 150 for free relative rotation with respect to the end 168. The roller 170 serves to guidingly track the inside end 168 of the arm 150 against the mullion 28 during opening movement of the upper door 32 and is maintained in resilient engagement with the mullion 28 during such movement by the tension spring 164. The arm 150 on the opposite side of the pivot pin 162 has a curved end 174 and it also is notched on its upper surface at 176. The curved end 174 is adapted to periodi- Cil cally tit into vertical interlocking engagement with an edge portion 178 on the latch plate 130 during certain phases of operation of the door opening operation as shown in FIGURES 4 and 10.

The plate 152 also supports a depending stop element 180 that maintains the arm 150 in a maximum inclined relationship with respect to plate 152, best Seen in FIG- URE 3.

The operation of the system 50 to produce the desired opening ratio between freezer door 32 and food storage compartment 38 in the illustrated embodiment of the invention is obtained as follows.

At the beginning of a door opening cycle of operation the power cylinder 70 is directly connected to the lower door 38 through the interconnecting linkage system 54. Further, the coacting latch mechanism 56 has the operatiye relationship shown in FIGURES 2 and 9 wherein the movable or pivotal latch plate is held in its stop position by the tension spring 134 and with the front shoulder 144 tipped toward the support plate 120 and the latch plate releasing arm has the curved end 174 thereon located above the shoulder 144 between it and the underside of the( plate 152, as best seen in FIGURE 9.

When the power cylinder 70 has pressurized fluid directed through the inlet conduit 78 into the cylinder on the side of the piston 74 opposite piston rod 76, the piston rod 76 is moved outwardly from the cylinder 70 against the interconnecting linkage system 54. Since the interconnecting linkage system 54 is directly connected to the lower door 38, the door 38 pivots about the vertical side axis defined by bracket assemblies 36, 40. As the lower door 38 is moved about this axis it carries the rods 90, 98 along a predetermined arc with respect to the vertical axis and the pivotal carriage 72 for the power cylinder 70 moves on the pivot pin 62 to compensate for the swinging movement of the door to thereby permit unrestrained translational movement of the piston rod 76.

The latch plate 130 will move forward with door 38 and engage catch element 156 to concurrently move door 32 from its closed position.

Following movement of doors 32, 38 to the open positions seen in FIGURE l, the latch plate 130 remains located against the vstop 138 and with its forward edge engaging the catch element 156. At this time, the latch plate releasing arm 150 has the roller 170 thereon moved from the mullion 28 between the door and the spring 164 resiliently urges the arm 150 against its stop 180, as seen in FIGURE 3. At this point the arm 150 is slightly inclined or tipped about the pivot pin 162 so that the curved end 174 is slightly spaced below the undersurface of plate 152. In this position the notch 176 in the curved end 174 is located in line with and forwardly of the edge 178 of the raised shoulder 144 on plate 130.

When the doors 32, 38 are moved closed from the position shown in FIGURE l by directing pressurized fluid to the piston rod side of piston 74, the piston rod 76 is retracted into the cylinder 70 and the rods 90, 98 and block 100 are pressed toward the doors 32, 38. The block 100 will swing the doors 32, 38 about the previously described side located vertical axis until the sealing gaskets 3S, 41 enga-ge the front of the cabinet so as to close access openings 30, 32. As the upper door 32 is moved into its closed position, the latch plate releasing arm 150 eventually has the roller thereon moved into engagement with mullion 28 and is thereby pivoted from its stop position in FIGURE 3 toward the reinforcing insert 148 on the front corner of the latch plate 130 until the notch 176 on the curved end 174 is positioned as seen in FIGURES 4 and l0. The arc of travel of curved end 174 displaces the latch plate 130 from its stop position in FIGURES 2 and 3 and causes pivotal movement thereof to a position as seen in FIGURE 4 when the top door 32 is in its closed position. The catch element 156 is located out of interconnecting aligned relationship with the forward edge of the plate 130 and the arm 150 has a slightly tilted position, as seen in FIGURE 10, and is located at a point just rearwardly of the insert 148 whereby upon a subsequent opening movement of door 38 the plate 130 will clear the catch element 156 and the curved end 174 of the release arrn 150 will ride from its vertically aligned interlocking relationship with plate 130 to a position above the rear part of the plate 130 as its moved forwardly by the lower door 38.

More particularly, when the mechanism 56 advances from the latch plate release position in FIGURE 4 when the power cylinder 70 is conditioned for a second door opening movement, the door 38 swings about its side vertical axis thereby moving the latch plate assembly 117 in an arcuate path away from the coacting latch mechanism subassembly 118 to a position as seen in FIGURE 5 wherein the movable latch plate 130 has cleared the catch element 156. When the catch element 156 is cleared, the subassembly 118 remains in its closed position whereby the upper door 32 is maintained closed while the lower door is moved open. Since door 32 remains closed, the curved end 174 of release arm 150 is maintained in the latch plate releasing position of FIGURE 4.

By virtue of the above-described structure and operation the door 32 thereby is opened one half as frequently as the lower door 38 or in other Words, the ratio between the door opening movements of lower door 38 and upper door 32 is 2: 1.

The final step in a cycle of operation of the automatic mechanical door opening system 50 is effected when the lower door 38 moves from the position shown in FIG- URE to carry the subassembly 117 of the coacting latch mechanism assembly 56 into the aligned position with subassembly 118 as seen in FIGURE 2. The latch plate 130 will pass under the catch element 156 which rides along the upper surface of the plate 130 thence forwardly across the inclined portion 142 and the raised shoulder 144 until the front edge of the plate 130 is in its interlocking relationship with catch 156, as seen in FIGURES 2 and 9. During the return movement, the curved end 174 of the releasing arm 150 also rides the upper surface of latch plate 130 so as to end up in the position interposed between the undersurface of plate 152 and the raised shoulder 144.

While the embodiment of the present invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted.

What is claimed is as follows:

1. A door opening mechanism for operating first and second swinging doors on a domestic refrigerator into their open positions at different frequencies comprising actuator means including a power cylinder having a reciprocating piston rod, linkage means for directly and continuously connecting said piston rod to a first door, said linkage means adapted to open the first door on each piston rod stroke, coacting latch means for alternately interconnecting the first door to a second door of the refrigerator, said coacting latching means including a latch plate, means for pivotally connecting said latch plate to one of the first and second doors, a catch element adapted to be xed to the other of the first and second doors, means for biasingly urging said latch plate toward a first predetermined stop position, said latch plate including a portion thereon operatively engaging said catch element when in its first predetermined stop position to interconnect the first and second doors for concurrent movement upon a first door opening operation of said actuator means, latch releasing means engaging said latch plate upon closing movement of the first door and operative to position said latch plate out of engagement with said catch element, said latch plate releasing means maintaining said latch plate out of interlocking engagement with said catch element upon movement of the first door produced by a second door opening movement of said actuator means -to produce alternate opening movement of the second door in response to opening movement of the first door.

2. A domestic two door refrigerator testing apparatus comprising actuator means including a power cylinder, means for pivotally connecting said power cylinder to the top of the refrigerator, said power cylinder including a reciprocating piston rod, an elongated link having one end secured to said piston rod and the opposite end thereof secured to a first door on the refrigerator, said piston rod and said link operating the first door upon each operation of said power cylinder, said elongated link extending across the front of a second door and engaged with a portion of the second door when the second door is moved from an open position to a closed position, coacting latch means for interconnecting the first and second refrigerator doors on alternate door opening movements of said piston rod, said coacting latch means including a movable latch plate on one of the first and second doors, a catch element fixed to the other of the first and second doors, means for operatively connecting said movable latch plate and said catch element during one door opening movement of said piston rod to cause concurrent opening movements of said first and second doors, and latch plate release means operatively engaging said latch plate following said one door opening movement to maintain said latching plate out of operative interconnecting engagement with said catch element when the doors are closed, said latch plate releasing means maintaining said latch plate out of engagement with said catch element upon a subsequent door opening movement whereby only one of the doors is opened in response to operation of said power cylinder, said latch plate being moved out of engagement with said latch plate release means on such door movement to operatively re-engage said catch element when the one door closes.

3. A door actuator system for automatically operating Iplural doors of a refrigerator to approximate two door domestic refrigerator use comprising actuator means including a power cylinder having a reciprocating piston rod, linkage means for connecting said piston rod to a first swinging door, coacting latch means for connecting said first door to a second swinging door, said latch means including a latch plate, means for pivotally connecting said latch plate to one of the first and second doors, a catch element fixed to the other of the doors, means for biasing said pivoted latch plate into a first stop position, said latch plate including an edge thereon located forwardly of its supporting door and rearwardly of said catch element in intersecting relationship therewith when both doors are closed, said latch plate edge engaging said catch element upon a first predetermined door opening movement of said piston rod to cause concurrent opening movement of the first and second doors, said linkage means connecting said piston rod to the first door being engageable with the second door upon closing movement of said piston rod to cause concurrent closing movement of the first and second doors, latch plate release means responding to the above-mentioned concurrent door closing movement to position said latch plate in a second stop position out of engaging alignment with said catch element, said release means maintaining said latch plate in its second stop position during an alternate door opening stroke of said piston rod to allow movement of the first door to its open position without moving the second door from its closed position, said latch plate release means including an elongated arm, means for pivotally supporting said elongated arm on the other of the first and second doors, means for biasing one end of said elongated -arm into a predetermined stop position, said elongated arm having a surface on said one end located in alignment with said forward edge of said latch plate and 9 10 being engageable therewith upon concurrent closing 2,361,040 10/ 1944 Larsen 49-104 X movement of said doors. 2,634,970 4/ 1953 Rosebrook 49-279 X References Cited DENNIS L. TAYLOR, Primary Examiner.

UNITED STATES PATENTS 5 U.S. C1. X.R. 2,075,937 4/1937 Graff 4'9-103 X 73-91, 112

2,218,505 10/1940 Chambers 49-103 

